In modern surgery one of the most important instruments available to medical personnel is the powered surgical tool. Typically this tool comprises some type of handpiece in which a motor is housed. Secured to the handpiece is a cutting accessory designed to be applied to a surgical site on a patient in order to accomplish a specific medical task. For example, some powered surgical tools are provided with drills or burrs for cutting bores into a hard tissue or for selectively removing the hard tissue. Still other powered surgical tools are provided with saw blades as the cutting accessories. These tools are used for separating large sections of hard and soft tissue. The ability to use powered surgical tools on a patient has lessened the physical strain of physicians and other personnel when performing medical procedures on a patient. Moreover, most surgical procedures can be performed more quickly and more accurately with powered surgical tools than with the manual equivalents that proceeded them.
While powered surgical tools have provided to be both an aid to patients and medical personnel, they are not without some disadvantages. A problem with some surgical tools is that the handpiece and associated instrument are assembled as a single, permanently attached unit. Consequently, if for a particular medical procedure, it is necessary to first drill a bore in a bone and then to cut an elongated slot through the bone, it may be necessary for the doctor to be provided with two tools, each with its own cutting accessory. Furthermore, for some tasks during the procedure the physician may want to use a tool with a head that is substantially axially aligned with the handpiece. For other tasks during the same procedure the physician may want to use a tool with a head that is angled relative to the handpiece. An advantage of using these tools is that they do not block the field of view around the surgical site as much as tools with in-line heads.
There have been attempts to provide powered surgical tool systems which allow for some interchangeability of the instruments with which the tool is used. Typically, these systems include a single handpiece that has a coupling assembly to which a number of different surgical cutting accessories can be attached. These systems allow the doctor working on the patient to switch the cutting accessory being used with the handpiece as the surgical procedure progresses. An advantage of these systems is that they significantly reduce the number of handpieces that need to be provided in a surgical setting.
There have been recent attempts to enhance the utility of handpieces by providing complementary attachments. An attachment serves as the head of the handpiece to which the cutting accessory is attached. Some attachments are provided with some types of linkages that transfer the motive power from the motor internal to the handpiece to the cutting accessory. For example, some attachments are designed to provide an extended length to the handpiece. Still other attachments function as bent-angle units. These attachments direct the associated cutting accessory at an angle away from the axis of the handpiece so as to provide the surgeon with an alternative view of the surgical site. Still other attachments transfer the rotor motion of the motor internal to the handpiece into either a reciprocating or oscillatory motion. These attachments make it possible to attach saw blades to handpieces that are normally used with rotating cutting accessories. The development of attachments has further expanded the utility of basic surgical handpieces.
While current multi-tool surgical tool systems have proved useful for reducing the number of tools needed when working on an individual patient, they are not without some disadvantages. Many current surgical tool systems are designed so that the individual elements forming a tool, the handpiece and the complementary accessory, must be threadingly coupled to each other. In some of these systems, in order to ensure a positive coupling, medical personnel are required to take a wrench to the tool in order to provide the torque required to first couple the elements, and then, at a latter time to uncouple them.
Moreover, if the handpiece is provided with an attachment in addition to a cutting accessory, at a minimum the medical personnel must take time to determine which component, the cutting accessory or the attachment, they are to remove from the handpiece. Moreover, if both the cutting accessory and the attachment are to be replaced, time must be spent releasing and restoring the lock mechanisms that hold both these members to the handpiece. At a minimum, the time medical personal spend performing these coupling and uncoupling tasks only increases the time it takes to perform the surgical procedure. However, the time needed to perform these tasks lengths the time it takes to perform the surgical procedure. Consequently, this lengthens the time the surgical site is open and exposed to infection as well as the time patient is exposed to anesthesia. Moreover, there are instances where the time medical personnel have to spend attending to the tool and not to the patient can potentially adversely affect the well being of the patient.
Moreover, in order for these interchangeable power tools to be properly designed, they should ideally be provided with some type of lock out mechanism to prevent tool operation in the event the instrument is not fully coupled in place.